1. Field of the Invention
This invention relates to a device for setting a photographic information value of a camera, such as film sensitivity, shutter time, an aperture value or the like and more particularly to an information setting device which electrically performs information setting and renewal in response to operation of a push-button or the like.
2. Description of the Prior Art
Heretofore, setting photographic information at variable circuit elements of a camera with an exposure control circuit varied the positions of the variable elements by manually operating mechanical information setting mechanisms such as an ASA dial, a shutter dial, an aperture ring and the like, which are interlocked with the variable elements. In photography, therefore, these setting mechanisms, which are disposed on the camera body or on a lens, must be operated separate from one another. This has hindered rapid photography.
To solve this problem, there have been proposed some information setting devices which set renewed information stepwise by a depressing a push-button with a counting circuit, such as a counter which performs counting action in response to depression of the push-button depressing operation. For example, the devices of the push-button type were disclosed in Japanese Laid-Open Patent Applications Nos. SHO 51-143327, SHO 52-33726, SHO 53-58233 and U.S. Pat. Nos. 4,081,813 and 4,191,458.
However, if the stepwise renewal speed is lowered in such a manner as in the prior art push-button type devices, a long period of time is required for information setting, which hinders rapid information setting. Conversely, is the stepwise renwal speed is quickened, the period of information renewal might become shorter than the time required for releasing the push-button from its depressed condition when a desired information setting value is obtained. Under such a condition, therefore, the desired information setting value tends to be shifted to another information setting value before the stepwise setting operation stops.
It is an object of this invention to provide an information setting device of the above type in which, when the information setting value reaches a frequently used value during the stepwise setting operation, the renewal speed or the ensuing shift to the next setting value which is less frequently used is reduced to prevent the frequently used setting value from being erroneously set. Frequently used information setting values are renewed quickly for sufficiently rapid information setting.
It is another object of the invention to provide an information setting device comprising an information setting switch which is manually shiftable from a first to a second condition; a pulse forming circuit which produces pulses at every predetermined period; a counter which detects the condition of the above switch and which sets information in a digital value by counting the number of pulses produced from the pulse forming circuit when the switch is in the second condition; detecting means which produces a detection signal when the count value of the counter reaches a value corresponding to a frequently used information setting value; and a correcting means which, in response to the detection signal of the detecting means, lengthens the pulse forming period of the pulse forming circuit more than the above predetermined period. The information setting device thus prevents erroneous setting of information setting values frequently used by the setting operator by solely reducing the renewal speed for such values while retaining the promptness of the information setting operation.
It is a further object of the invention to provide an information setting device which shifts a setting value stepwise every time a push-button is depressed and also automatically and continuously shifts the setting value step by step when the push-button is continually depressed. The device is characterized by an arrangement to prevent erroneous setting of a normal frequently employed value by extending the period for shifting the normal frequently employed value to a next setting value to a period greater than the period for shifting other values when the setting value reaches the frequently employed value during the stepwise continuous setting operation. In this manner erroneous setting of a normal frequently employed setting value can be prevented.
These and further objects and features of the invention will become apparent from the following detailed description of preferred embodiments thereof taken in conjunction with the accompanying drawings.